Variable volume pump



Sept. 9, 1969 P. HARTMANN 3,465,682

VARIABLE VOLUME PUMP Filed OCT. 26, 1967 2 Sheets-Sheet l /NVEN TOR- PH/L IP HARTMANN I [1/ MW ATTORNEY p 1969 P. HARTMANN 3,465,682

VARIABLE VOLUME PUMP Filed Oct. 26, 1967 2 Sheets-Sheet 2 PH/L /P HARTMA NN A TTOPNE V United States Patent U.S. Cl. 103120 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to a variable volume pump. This type of pump is commonly known and includes a circular working chamber which encompasses a rotor having vanes radially projecting therefrom for engagement with the circular chamber wall. Further, the heretofore known variable volume pumps have ported rings surrounding the rotor and movable with respect to the rotor and providing the working chamber described, for the purpose of varying the capacity of the pump. Such type of pump is shown in my US. Patent 3,221,665.

My previous patent also shows the use of pockets for hydraulicly balancing the working force on the surrounding ring which is ported. It further shows the rotor vane to have an offset outer end or tip which is subjected to outlet pressure for holding the vane against the wall of the working chamber defined by the port ring. The pump art is also aware of drivingly relating the rotor and the pump shaft without any axial thrust therebetween, and it is aware of hydraulicly balancing the rotor, both of these features being in certain arrangements and types of pumps, such as the constant volume pump.

The present invention provides a variable volume pump which does not require any port plates, nor any mechanical or antifriction bearing for the rotor nor does it require any support or mechanical bearing for resisting rotor axial thrust. Speaking positively, the rotor is free of any axial thrust and it is free to seek its own position within the housing, and the rotor is hydraulicly balanced against the pressure created in the working chamber. That is, the rotor is free of the shaft, except for a drive relation therebetween, so the rotor is supported independent of the shaft without axial thrust which may exist in the shaft, and the rotor is susceptible to the hydraulic balancing mentioned.

Therefore, the only mechanical force on the rotor is the force created in the rotation or by the turning torque in the operation of the pump. The rotor is thus pressurecompensated, and this eliminates the hydraulic force created in the pumping operation, including the forces on the rotor transverse to the axis thereof and the force on the movable ring to the side thereof opposite the side having the working chamber.

This entire arrangement provides for a more efficient pump, and for the provision of two pumping units or sections in one device for maximum capacity, such as obtainable in a minimum size of pump. Further, no mechanical bearings are required for support of the rotor, and the entire unit is of a minimum operating noise level for a maximum of speed and pumping capacity.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a sectional view of one embodiment of this pump, and taken along the broken line 11 of FIG. 2.

FIG. 2 is a sectional view taken along the broken line 2-2 of FIG. 1.

FIG. 3 is a face view of a central portion of another embodiment of this pump invention, and with the view taken along the line 33 of FIG. 4.

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3, and showing the double-pump embodiment.

FIG. 5 is a diagrammatic view of the rotor showing the forces acting thereon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the pump arrangement in a central sectional view which shows, along with FIG. 2, a single rotor or pumping unit in the device. FIG. 4 is the same construction or arrangement as FIGS. 1 and 2, except that two rotors or pumping units are shown in one device. FIGS. 1 and 2 show the pump housing to include the end pieces 10 and 11, and the center piece 12. These three pieces are suitably bolted together, such as by bolts shown in FIG. 1 and indicated by identified bolts 13. The interior of the central section or piece 12 includes a circular wall 14 defining a cylindrical opening within the housing. An unported ring 16 is movably disposed in the housing hollow interior 17, and FIG. 1 shows that the ring 16 would move from left to right between the limits defined by the housing wall 14. An adjusting screw 18 extends through a cover 19 secured to the housing piece 12. A compression spring 21 is abutably related to the screw 18, and a bearing member 22 abuts the other end of the spring 21. The bearing 22 in turn abuts a pin 23 which extends to the interior of the housing piece 12 and is in abutment with the ring 16 at the area designated 24. Thus the ring 16 can be moved to the right, as viewed in FIG. 1, by the adjusting means described.

The ring 16 is without passageways or ports extending radially therethrough, and the ring has a central circular opening 26. A pump rotor 27 is rotatably disposed within the ring 16, and the rotor has vane slots 28 radially disposed therein for radially slidably supporting vanes 29. Thus the vanes 29 may extend and contract from their intermediate positions shown in FIG. 1, as the vane slots 28 provide room for radial retraction, and movement of the ring 16 to the right in FIG. 1, would provide room for the vanes to extend from the rotor 27 on the right side, as viewed in FIG. 1.

It will be further noted that the vanes 29 have offset portions 31 on their outer ends, and the rotor body 27 has slotted openings 32 for receiving the offset projections 31 when the vane is fully retracted into the body 27. The vane offset tips or ends 31 provide a radially inwardly faced projection under which hydraulic pressure can exist for holding the vane radially outwardly and against the ring surface 26, as desired for efficient sealing between the vane 29 and the ring 16. Further, the rotor piece 27 is provided with fluid passageways extending from the outer circumference 33 and to the inner end of the vane slots 28, such as the shown passage 34. Of course each of the vane slots 28 would have a passage 34 so that high pressure could exist at the base of the vane slot 28 to hydraulically force the vanes 29 radially outwardly as desired.

Of course at the time when the particular vane 29 does not have its high pressure passageway 34 exposed to the Working chamber or high pressure area of the pump, it is then significant that the offset vane tip 31 is available for holding the vane radially outwardly. This is the time when the vane in question is completing its scaling in the working chamber and is moving to the transition position toward the inlet or suction side in the ring 16. This would be to the left as viewed in FIG. 1, since the inlet opening is indicated to be at the lower half of the rotor and is indicated by the dotted line designated 36, while the outlet or high pressure passageway is indicated at the upper half of the rotor, and is indicated by the dotted line designated 37. That is, the passageway 34 is no longer exposed to high pressure when the ring 16 is moved to the right from the position shown in FIG. 1, and the pump is therefore pumping and is not in the neutral position shown. At that time, high pressure is desired under the offset tip 31 for holding the vane outwardly as it moves through the area designated on the left in FIG. 1, as the pump is rotating in the direction of the arrow indicated R in FIG. 1.

It will therefore be understood that the working chamber is above the rotor, and the hydraulic force would therefore be downward on the rotor piece 27, and it would be upward on the movable ring 16. A thrust block 38 is in contact with the ring 16 and bears downwardly thereon to counter the upward hydraulic pressure mentioned. Roller bearings 39 are interposed between the block 38 and a counter block 41 for permitting anti-friction movement of the ring 16, as desired. A cap 42 is suitably bolted to the top of the housing piece 12 for enclosing the parts described.

FIGS. 1 and 2 further show that the rotor, which includes the piece 27 and the vanes 29, also has cylindrical end pieces 43 and 44. The rotor has a hollow central opening 46, and this opening has splines 47. A shaft 48 is extending into the rotor, and it also has a splinder end 49 for rotationally relating to the rotor. However, the motor and shaft are free to move axially of each other, and therefore the rotor is free to locate itself between the faces 51 and 52 of the housing pieces and 11, respectively. Therefore, any axial thrust on the shaft 48 is not transmitted to the rotor which is therefore relieved of any such mechanical force. Ball bearings 53 are secured in the housing piece 10, and they provide the rotational support for the shaft 48, and a snap-ring 54 provides a degree of thrust control for the shaft 48.

Also, an end plate 56 surrounds the shaft 48, and it is suitably bolted to the housing piece 10 and may be removed therefrom, just as the bearings 53 and snap-ring 54 are removable. Therefore, the shaft 48 can be readily removed and it can be replaced by any other shaft and this provides for interchanging the shaft 48 without disassembling the pump.

FIG. 3 is further descriptive of the embodiment in FIGS. 1 and 2 in that it shows the inlet channel 36 and the outlet channel 37, and these are shown to be respectively in flow communication with the inlet passageway 57 and the outlet passageway 58, both of which extend from the channels 36 and 37, respectively, and to the exterior of the pump.

Therefore, working pressure is created at the upper half of the rotor piece 27, when the ring 16 is shifted to the right from the position in FIG. 1. The total hydraulic force created in the working chamber described exerts itself downwardly on the rotor piece 27, and this force is hydraulicly balanced in a manner here and after described. FIG. 2 shows the outlet passageway 58 to be in flow communication with a passageway 59 which leads to a pocket of crescent shape and designated 61. This pocket is formed in the housing piece 10 and is defined in part and therefore exposed to the rotor end 43 as it extends over the lower half of the rotor end 43, as indicated in dotted lines in FIG. 1. Also, a passageway 62 extends from the outlet 58 in the housing 10, and it connects to the passageway 63 in the housing piece 12, and, in turn, these connect to a passageway 64 in the housing piece 11. Finally, a passageway 66 extends upwardly to a pocket 67 formed in the piece 11 and surrounding the lower half of the rotor end 44, just as with regard to the pocket 61 4 in its shape and configuration. The pockets 61 and 67 are of a location and shape and size to substantially counterbalance the hydraulic force acting downwardly on the rotor piece 27 in the working area described, which is basically in the location of the channel 37. FIG. 5 shows the downward force on the rotor to be designated A, and it shows the counterbalancing forces on the rotor as created by outlet pressure in the pockets 61 and 67 to be designated one-half of the force A or A/Z. Therefore, the hydraulic radial force acting on the rotor piece 27 is counterbalanced. It is possible to have the forces acting upwardly on the rotor piece 27 to be slightly greater than the downward force A to therefore hold the rotor ends 43 and 44 upwardly against the cylindrical bores 68 and 69 in the housing pieces 10 and 11 respectively. This therefore will firmly hold the rotor piece 27 without any vibration or the like. Of course it could also be that the downward force on the rotor is greater than the upward force created in the pockets 61 and 67, so that the rotor is held downwardly by a slightly greater force, to again avoid vibration or chatter in the operation of the pump.

It will therefore be noted that the inlet and outlet channels 36 and 37 are arranged directly in the housing piece 10 and are located, shaped, and sized so that the shifting of the ring 16 will not affect the passage of fluid through the channels 36 and 37. Therefore no ported ring 16 is needed, and no port plates are needed, though the pump is a variable volume type.

The invention as applied to the double unit pump of FIG. 4 is the same as described, except that a single central housing piece 71 is used to conduct and guide the fluid with respect to the pump units on each side of the piece 71 and containing the rotors 27. Thus the piece 71 has an inlet opening 72 which extends to both rotor pieces 27 for supplying inlet fluid, and it has an outlet passage 73 and an outlet passage 74, both being disposed and shaped such as the passage 58 and its attending channel 37. Also, the double unit has the hydraulic balancing pockets 61 and 67, such as described in connection with FIGS. 1 and 2. Finally, the double unit has an end piece 76 which presents its circular bore 77 for rotational support of the rotor 27, and the double unit has an end piece 78 which presents a circular bore 79 for support of the end of the other rotor 27. Also, a shaft 81 extends through the double unit and is of course splined at 82 and 83 for rotational drive connection with the rotors 27, but again there is no axial thrust or mechanical force transmitted between the rotors 27 and the shaft 81. Also, again the shaft 81 can be removed from the unit, without disassembly of the unit other than removal of the end plate or piece 84 and the bearings 86 and snap-ring 87.

Also in the double unit, just as in the single unit described, no ball, needle, or other mechanical bearings are required for support of the rotor, and such bearings are usually made with some clearance or play therein, and therefore undesirable. In this instance, the rotor ends 43 and 44 are placed directly into the housing bores 68 and 69, and are likewise placed in the double unit in FIG. 4. This therefore permits very close tolerances and a highly eflicient pump, along with the fact that the rotor 27 is hydraulically balanced through the balancing pockets 61 and 67.

Shown throughout the views are conventional O-ring sealing members, such as the O-ring 88 shown in the groove 89, in FIGS. 4 and 3, respectively.

It is also interesting to mention that since the housing pieces themselves have the fluid inlet openings and the fluid outlet openings, no port plates are required and the ring 16 is not ported since it is not required to be. Therefore, no plates are bolted to the opposite faces of the rotor piece 27, and therefore the port or passageway 34 can be provided for.

Also notice that the working chamber extends coextensive with the high pressure area of the pump, and

that is across the upper half of the rotor 27. Since the outlet opening 37 does not extend to the area surrounding the line of abutment between the adjustable control 23 and the piece 16, the highest fluid pressure is created in that area. So the fluid pressure urges the ring 16 to the left in FIG. 1, and against the pin or control 23, so no counterbalancing control is needed in contact with ring 16 on the side diametrically opposite abutment line 24.

The rotor 27 has its bearing pieces 43 and 44 integral thereon, and they are rotatably journaled in the housing bores 68 and 69. The shaft 48 is rotatably supported in bearings 53 which are piloted in the housing piece 10. So, the rotor 27 and shaft 48 are rotationally keyed together with axial freedom therebetween, and also with radial play therebetween to any degree of tolerance desired as long as the two rotate together. So their bearings are separate and independent of each other, and each is free to align with its own bearings. The particular arrangement of fluid inlet and outlet openings permits this.

I claim:

1. A variable volume pump including a housing having a fluid inlet opening and a fluid outlet opening and an intermediate chamber, a piece movable in said intermediate chamber and having a circular opening, an adjustable control operatively connected to said piece for moving the latter in said housing, a rotor rotatably disposed in said housing and including vanes slidable on said piece in said circular opening, said rotor defining a working chamber on one radial side of said rotor and being coextensive with the high pressure area of said pump, a shaft operatively connected to said rotor for rotation therewith and extending from said housing, the improvement comprising said fluid inlet opening and said fluid outlet opening both being fully disposed in said housing and located and shaped to be in direct fluid-flow communication with said circular opening in all adjusted positions of said piece, said rotor including a circular bearing piece extending on each end of said rotor, said housing having a circular bore snugly receiving each of said bearing pieces and presenting a fixed bearing for the rotation of said rotor, said shaft and said rotor being operatively connected through a rotational drive keyed connection and are free to move axially relative to each other, said housing having a fluid pocket in a portion of each of said bores and on the radial side of said rotor diametrically opposite said working chamber and witheach of said pockets being of a radially projected area one-half the radially projected area of said working chamber to fluid-pressure balance the hydraulic pumping force in said working chamber, and fluid passageways extending from said fluid outlet opening to each of said pockets for presenting fluid outlet pressure in each of said pockets.

2. The subject matter of claim 1, including in said housing a single piece having two of said fluid inlet openings and two of said fluid outlet openings, and two of said rotors respectively in fluid-flow communication with respective ones of said inlet openings and said outlet openings.

3. The subject matter of claim 2, wherein said shaft extends into said housing and is drivingly operatively connected to each of said rotors.

4. The subject matter of claim 3, including an antifriction bearing interposed between said shaft and said housing and being removable from said housing, and said shaft being axially slidably removable and replaceable with respect to said rotors, independent of removal of said rotors from said housing.

5. The subject matter of claim 1, wherein the total area of said radially projected areas of both said fluid pockets is slightly diiferent from the size of the radially projected area of said working chamber to fluid-pressure urge said circular bearing pieces of said rotor into snug contact with said housing bores under the influence of the total hydraulic forces acting on said bearing pieces and said rotor.

References Cited UNITED STATES PATENTS 920,976 5/1909 Minor. 2,612,114 9/1952 Ernst. 3,221,665 12/1965 Hartmann 103-136 DONLEY J. STOCKING, Primary Examiner W. J. GOODLIN, Assistant Examiner U.S. Cl. X.R. 103-136 

